The most common retro-reflectors found in everyday applications are corner cubes composed of three orthogonal mirrors, corner cube pyramid shaped prisms and microspheres made out of glass or various plastics. Microspheres are commonly used in the textiles industry for either aesthetic reasons or in order to provide higher night visibility features to fabrics. Retro-reflectors find many uses including many related to promoting health, safety or welfare. For example, retro-reflection technology is commonly used in highway safety applications. Roads and street signs can include retro-reflectors to increase their visibility at night. Light from an oncoming vehicle's headlights is reflected back towards the vehicle operator's eyes by appropriate retro-reflectors embedded in lane markers or included with road signs. Garments worn by highway workers can include retro-reflectors so that the workers are more readily seen during night road work operations.
U.S. Pat. No. 4,336,092, entitled “Retroreflective Fiber and Method of Making Same” and issued 22 Jun. 1982, appears to relate to making a thread-like continuous retro-reflective fiber. A thread-like fiber is made by laminating a thin film of retro-reflective material to a supporting polyester film, and then slitting the laminate to form narrow strips of retro-reflective material having sufficient strength to be combined with other fibers to form a composite yarn having retro-reflective characteristics, which composite yarn may then be woven, knitted, or spun to provide a fabric having retro-reflective characteristics.
U.S. Pat. No. 5,962,108, entitled “Retroreflective Polymer Coated Flexible Fabric Material and Method Of Manufacture” and issued 5 Oct. 1999, appears to relate to a process and article for a retro-reflective polymeric coated flexible fabric material having a retro-reflective layer and a polymeric compatibilizing layer welded to a polymeric coated outer surface of a flexible fabric material. The compatibilizing layer provides an intermediate layer between the retro-reflective layer and the flexible fabric material to create bond strength between dissimilar polymers.
US Patent Application Publication 2007/0062433, entitled “Abrasion Resistant Omnidirectionally Reflective Rope” and published 22 Mar. 2007, appears to relate to a flexible abrasion resistant omnidirectionally reflective rope having a central braided high strength core comprising gel fiber or p-aramid fibers that is surrounded by a cylindrically braided sleeve of reflective strips composed of narrow width reflective strips that comprise a woven or knitted narrow width strip and a flexible nylon retro-reflective sheet sewn thereon and covered with abrasion resistant coating. It appears that the flexible retro-reflective sheet is formed by thermally bonding corner cube, microsphere retro-reflectors, or wide angle exposed retro-reflective lenses to a flexible polymeric sheet. Due to its braided construction, the reflective rope is described as reflecting light omnidirectionally over a large angle of acceptance, thereby providing an improved measure of safety in the marine craft environment.
Although known retro-reflectors and techniques for using them have proven useful, there are disadvantages and drawbacks. Room for improvement remains and would be a welcome advance in the art.